Field of the Invention:
The invention relates to a fuel nozzle configuration for a fluid-fuel burner having a main axis, a backflow region, a fuel nozzle and an inflow region for generating a swirl flow of fuel in the inflow region. The invention furthermore relates to an oil burner using such a fuel nozzle configuration and to a method for regulating the fuel supply of a fluid-fuel burner.
In fluid-fuel burners, particularly in a gas turbine, the fluid fuel is injected into a combustion chamber through a fuel nozzle configuration. It is necessary for the fuel quantity being supplied to be controlled as a function of the thermal output to be generated and of the hot-gas quantity occurring as a result of the combustion of the fluid fuel. If the fuel quantity is fed constantly into the fuel nozzle configuration, that regulation of the fuel quantity can be achieved by bringing about a backflow of fuel out of the fuel nozzle configuration without the fuel being introduced into the combustion chamber.
East German Patent 22 076 describes an atomizer having a return regulation for liquid fuels, for example for gas turbine plants, in which an improvement in an operation of closing an outlet orifice in the atomizer is to be achieved. Fuel is supplied to a swirl chamber through tangential supply ducts in the atomizer. Perforations are provided in the bottom of the swirl chamber through which the fuel quantity to be returned is returned through one or more return ducts and a return conduit into a fuel tank, but the perforations are not specified in any more detail. German Published, Non-Prosecuted Patent Application DE 32 35 080 A1 likewise deals with the structure of an outlet orifice of an injection nozzle. A return injection nozzle described therein for a gas-turbine burner has a cylindrical return needle in the flow return.